In order to increase the potential and trend prediction accuracy of unconventional oil and gas resources, a potential and trend prediction method of unconventional oil and gas resources based on combination forecasting model of variable weight for multi-factor is proposed. First of all, the present situation and trend of oil and gas resources development are analyzed and introduced. It is pointed out that it is influenced and restricted by many factors and external environment, which shows the characteristics of its complexity and non-linear historical evolution trend. Secondly, the optimal variable weights are determined by using the variable weight combination forecasting model and then the potential and trend prediction accuracy of unconventional oil and gas resources is realized to be increased. Finally, the validity of the proposed method is verified by the simulation experiment.